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  • Aim: How do we solve equations that contain more than one function?


At the end of this lesson, you will be able to...
  1. apply previously learned identities to express an equation in terms of one trigonometric function
  2. solve the resulting equation for all values of the angle in the interval 0°<x<360°

For this lesson you wiil need to have in front of you: the Pythagorean Identities, the reciprocal identities, and the quotient identities.
  • Write them on this page of your notebook.

You will use these to change from an equation with two trig functions into an equation with only one trig function.

Here are some videos demonstrating this:


Video 1



For this video, only watch example 1


Video 2


As you can see, all equations must be written in terms of one trig function


  • Classwork: Now try these

  1. Find the solution for 2sinx = 3 cotx for the interval 0< a < 2pi (Answer: pi/3 and 5pi/3)
  2. Find all values of x in the interval 0° < x < 360° such that 2sinx + 1 = cscx (Answer: 30°, 150°, or 270°)

  • Homework: Complete #3-13 odd.

Mixed_Trig.JPG

  • Answers

A-Mixed_Trig.JPG

  • Journal entry: A trigonometric equation that contains more than one function is like an equation with two variables. Compare and contrast the techniques that are used to solve equations with two variables with trigonometric equations that contain more than one function.